526
J Gaussian, S.I., and Atomic Units
The magnetic moment of a particle with charge Q and mass m, moving with angular
momentum L, is
μ =
Q
2mc
L.
The Poynting vector, which is an energy flux (energy/(area-time)) is
S =
c
4π
E×B.
Ohm’s Law is
J Q = σ E
where J Q is the charge current and σ is the conductivity.
J.1.1 Physical Quantities Expressed in Gaussian Units
Electric field E∼
√
g
s
√
cm
,
Magnetic field B∼
√ g
s
√
cm
,
Charge Q∼
g·cm 3
s
,
Angular momentum∼L∼
gcm 2
s
.
Energy∼erg =
g·cm 2
s 2 ,
Poynting vector∼
energy
area·time
∼
g
s 3 =
erg
cm 2 ·s
Force=QE∼dyne = ∼
s·cm
s 2 .
Magnetic dipole moment = μ∼
√
g cm 5/2
s
.
Conductance∼σ = ∼
1
s
.
Charge current∼J Q =
Q
s·cm 2 ∼
√ g
s 2 √
cm
.
(J.2)
J Gaussian, S.I., and Atomic Units
The magnetic moment of a particle with charge Q and mass m, moving with angular
momentum L, is
μ =
Q
2mc
L.
The Poynting vector, which is an energy flux (energy/(area-time)) is
S =
c
4π
E×B.
Ohm’s Law is
J Q = σ E
where J Q is the charge current and σ is the conductivity.
J.1.1 Physical Quantities Expressed in Gaussian Units
Electric field E∼
√
g
s
√
cm
,
Magnetic field B∼
√ g
s
√
cm
,
Charge Q∼
g·cm 3
s
,
Angular momentum∼L∼
gcm 2
s
.
Energy∼erg =
g·cm 2
s 2 ,
Poynting vector∼
energy
area·time
∼
g
s 3 =
erg
cm 2 ·s
Force=QE∼dyne = ∼
s·cm
s 2 .
Magnetic dipole moment = μ∼
√
g cm 5/2
s
.
Conductance∼σ = ∼
1
s
.
Charge current∼J Q =
Q
s·cm 2 ∼
√ g
s 2 √
cm
.
(J.2)